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排序方式: 共有135条查询结果,搜索用时 15 毫秒
91.
LAURIE A. HALL PER J. PALSBØLL STEVEN R. BEISSINGER JAMES T. HARVEY MARTINE BÉRUBÉ MARTIN G. RAPHAEL S. KIM NELSON RICHARD T. GOLIGHTLY LAURA MCFARLANE‐TRANQUILLA SCOTT H. NEWMAN M. ZACHARIAH PEERY 《Molecular ecology》2009,18(24):5074-5085
Genetic assignment methods provide an appealing approach for characterizing dispersal patterns on ecological time scales, but require sufficient genetic differentiation to accurately identify migrants and a large enough sample size of migrants to, for example, compare dispersal between sexes or age classes. We demonstrate that assignment methods can be rigorously used to characterize dispersal patterns in a marbled murrelet (Brachyramphus marmoratus) population from central California that numbers approximately 600 individuals and is only moderately differentiated (FST~ 0.03) from larger populations to the north. We used coalescent simulations to select a significance level that resulted in a low and approximately equal expected number of type I and II errors and then used this significance level to identify a population of origin for 589 individuals genotyped at 13 microsatellite loci. The proportion of migrants in central California was greatest during winter when 83% of individuals were classified as migrants compared to lower proportions during the breeding (6%) and post‐breeding (8%) seasons. Dispersal was also biased toward young and female individuals, as is typical in birds. Migrants were rarely members of parent‐offspring pairs, suggesting that they contributed few young to the central California population. A greater number of migrants than expected under equilibrium conditions, a lack of individuals with mixed ancestry, and a small number of potential source populations (two), likely allowed us to use assignment methods to rigorously characterize dispersal patterns for a population that was larger and less differentiated than typically thought required for the identification of migrants. 相似文献
92.
Charles D Criscione Claudia LL Valentim Hirohisa Hirai Philip T LoVerde Timothy JC Anderson 《Genome biology》2009,10(6):R71-13
Background
Schistosoma mansoni is a blood fluke that infects approximately 90 million people. The complete life cycle of this parasite can be maintained in the laboratory, making this one of the few experimentally tractable human helminth infections, and a rich literature reveals heritable variation in important biomedical traits such as virulence, host-specificity, transmission and drug resistance. However, there is a current lack of tools needed to study S. mansoni's molecular, quantitative, and population genetics. Our goal was to construct a genetic linkage map for S. mansoni, and thus provide a new resource that will help stimulate research on this neglected pathogen. 相似文献93.
Gustavo?Camps-VallsEmail author Alistair?M?Chalk Antonio?J?Serrano-López José?D?Martín-Guerrero Erik?LL?Sonnhammer 《BMC bioinformatics》2004,5(1):135
Background
This paper presents the use of Support Vector Machines (SVMs) for prediction and analysis of antisense oligonucleotide (AO) efficacy. The collected database comprises 315 AO molecules including 68 features each, inducing a problem well-suited to SVMs. The task of feature selection is crucial given the presence of noisy or redundant features, and the well-known problem of the curse of dimensionality. We propose a two-stage strategy to develop an optimal model: (1) feature selection using correlation analysis, mutual information, and SVM-based recursive feature elimination (SVM-RFE), and (2) AO prediction using standard and profiled SVM formulations. A profiled SVM gives different weights to different parts of the training data to focus the training on the most important regions. 相似文献94.
95.
Recombinant adenovirus is one of the primary vectors for human gene therapy. However, the aggregation of unstable virus has
been a recurring problem during the production of purified virus for human therapeutics. To facilitate the development of
a robust manufacturing process for recombinant adenovirus vectors, a convenient and reliable size distribution analytical
assay is necessary and we demonstrate here that disc centrifuge sedimentation is applicable to this purpose. Using the disc
centrifuge system and the line start method, the assay can provide particle size distribution of adenovirus samples within
30 min. The assay can detect virus concentrations down to 0.01% (w/v) or 3 × 1011 particles per ml. The apparent hydrodynamic diameter of recombinant adenovirus was determined to be about 0.063 μm. Furthermore,
the disc centrifuge analysis was able to detect adenovirus dimers, trimers, and tetramers, consistent with a rigid sphere
approximation for adenovirus, as well as a large aggregate of 0.35 μm. The appearance of viral aggregates is confirmed by
increased light scattering based on A320/A260 ratios. The technique could be useful for monitoring the kinetics of aggregation for adenovirus and other DNA and RNA viruses
in the submicron region. Therefore, this novel assay provides a critical tool for purification development of viral vectors
for meeting therapeutic and research needs.
Received 18 September 1997/ Accepted in revised form 15 May 1998 相似文献
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